Method for separating materials of different specific gravities



July 14, 1925.

T. M. CHANCE METHOD FOR SEPARATTNG MATERIALS OF DIFFERENT SPECIFICGRAVITIES INVENTOR.

Filed Oct. 14, 1921 WITNESSES:

Patented July 14, 1925.

UNITED STATES THOMAS CHANCE, OF PHILADELPHIA, PENNSYLVANIA.

METHOD FOR SEPAR ATING MATERIALS OF DIFFERENT SPECIFIC GRAVITIES.

Application filed October 14, 1921. Serial No. 507,605.

To all whom it may concern:

Be it known that I, THOMAS M. CHANGE, a citizen of the United States,residing at Philadelphia, in the State of Pennsylvania, have inventedcertain new and useful Improvements in Methods for Separating Materialsof Different Specific Gravities, whereof the following is-aspecification.

My invention consists of an improvement upon the method of separatingmaterials of different specific gravities described in U. S. atent No.1,224,138, which was issued to me May 1, 1917, and consists of animproved method for discharging the heavier mate- 1 rial which sinksthrough the fluid mass used as the separating medium to the lower partof the receptacle in which separation is effected, by suppressingagitation of the fluid tus thus permitting some of the solid constituentof the fluid mass to settle with the heavier material and using thissettled matter as a conveying medium to carry the said heavier materialout of the apparatus. The

fluid mass used to efiect separation is similar to that described in theabove namedpatent as an agitated mixture of liquid and comminuted solidmatter insoluble in said liquid.

In my present invention I permit some of the solid constituent of thefluid mass, as well as materials to be separated that are of greaterspecific gravity than the fluid mass, to settle to the lower part of thereceptacle in which separation is effected, and I discharge theseheavier materials, generally consisting of concentrate in the treatmentof ores, and of refuse in the washing of coal, together with the solidconstituent of the 40 fluid mass, from the "lower part of the saidreceptacle. This discharge may be eflected by causing the materials toflow through a restricted discharge operating by the same method used toeffect the discharge of relatively thick, semi-fluid, or more or lessviseid materials when what are known .as spigot discharges are used todischarge such mate rials from a classifier, settler, jig hutch or othersimilar apparatus; or, the discharge may be effected by trapping outthrough two or more valves superposed one above the. other and which arealternately opened and closed, as is practiced in the operation ofapparatus similar to the well known Robinson coal washer; or thematerial may be removed by bucket elevators, scrapers or other devicesin common use, etc. After removmg the material in this way the solidconstituent of the fluid mass is separated from the materials with whichit is mixed by screenlng, washing with water, by classification in anupward current classifier, or other meanswand may then bereturned to theapparatus for re-use in the fluid mass.

I It is of course evident that when operatmg by this method, theagitation used to maintain the fluidic properties of the fluid mass mustbe less than that required to prevent settlement of any of thecomminuted solid matter forming the solid constituent "0 of the fluidmass, and in practice I find that the agitation can readily be adjustedto pro- 'd'uce the required condition. mass in the region at the base ofthe appara- It will-be understood that the heavier materials to beremoved from the lower part of the apparatus are no longer in a fluidmass, but are mixed with, and encased in, a mass consisting of the solidconstituent of the fluid mass with liquid filling-its interstices orvoids and with the body of the fluid mass superposed thereon, whichfluid mass is maintained in a fluidic condition by agitation.

In addition to the removal of the heavier material from the lower partof the apparatus as already described I may utilize the conditionsproduced therein to efl'ect a three or four part separation by drawingoff, from position intermediate the top and bottom of the fluid mass, aportion of the fluid-mass together with materials of intermediatespecific gravity, thussecuring the separation of -middlings productswhichare too heavy to float in the fluid mass and are not heavy enoughto sink quickly through it.

The drawing illustrates the carrying out of my invention in a cone typeapparatus resembling in its structural features the well known Robinsoncoal washer. It will be understood however that the receptacle used maybe of any suitable shape or form, that the required agitation may beeflected by any of the described means, andthat the materials may beremoved by any suitable meansin common use in coal washers and oreconcentrators, such as bucket elevators, scrapers, rakes, conveyors andthe like.

It will be understood that for effective carrying out of myfinventionthe fluid mass must he maintained as a mobile fluid, that is, itsfluidic properties must at all times be such as to permit the heavier ofthe materials to be separated to fall freely through it.

An apparatus in which this method of separation may be carried out isillustrated by the figure of the drawing which is a vertical elevationand partly cross-sectional view embracing the essential and necessaryelements and also some adjunct-ive devices which are useful in handlingand rehandling the solidconstituent of the fluid mass and the separatedmaterials.

The drawing represents the receptacle as a cone, which diagrammaticallyis intended to represent a receptacle of any suit-able shape or size,equipped with means for mechanical agitation of the fluid mass shown asa revolving shaft 3, with attached stirring arms 4, driven by bevelgears 5, and equipped Withmeans for hydraulic agitation consisting ofinlets 6, for liquid under pressure controlled by a valve 7, and meansfor discharging material settling to the lower part of the apparatuscomprising a discharge tube 8,.con-

, trolled by a slide vvalve 9, operated by a thrust cylinder, and alsoprovided with a hydraulic jet inlet 11, controlled by the valve 12, tofacilitate the flow of settled material through the valve 9. Below thisdischarge valve 9 a shaking screen 13 is shown, actuated by theeccentric 14. This screen is supported on rollers 15. It dewaters anddesands the material delivering the sand and waterlinto the settlingtank 16, the separated material being delivered from the upper deck ofthe screen 13. The receptacle 1 is provided with an overflow weir andapron 17 whichis intended diagrammatically'to represent any means fortransporting material floating in the upper part of the fluid mass 2,and removing it from the apparatus, which-delivers the materialconsisting of separated (floating) material, fluid mass and liquid(water) 18, superimposed on fluid mass 2, to the des'anding anddewatering shaking screen 19, the upper deck of which delivers theseparated material dewatered and desanded. The separated water and sandflow through the conduit 20 to the settling tank 16, from which the sandmixed with suflicient water is pumped by the pump 21, through conduit'21, back into the receptacle 1. Clear liquid (water) from the settlingtank -'16, is pumped by pump 22 through the conduits shown tosupplyhydraulic agitation through inlet' 6, and for hydraulic flushingjet 11, and also for supplying the spray nozzles 23, .23 .for thedesanding screens 13 and -19. The material to be-separated is introducedthrough a feed chute shown as an inclined trough 24. The

liquid (water) 18, overlying the fluid mass is shown by broken lines,the fluid mass 2, by broken lines andstippling to represent its solidconstituent, and the settled material 25, in the lower part of thereceptacle and. discharge tube 8, is shown by stippling.

An aperature 1n the side of the receptacle 1, controlled by a gate 26,and operating lever 27, and provided with a dischargeapron 28, is shownto illustrate diagrammatically a means for drawing ofi material that isnot light enough to float readily in fluid mass 2, and which is notheavy enough to sink readily in said fluid mass.

Such material may be desanded and de watered by screens similar to 13and 19, or any other apparatus in common use for such purposes.

The operation of this apparatus will be readily understood withoutfurther detailed description. It will be understood that the agitationmay be effected either by hydraulic or by mechanical means, that eitherthe hydraulic water or the operation of the revolving shaft 3 may bediscontinued, or that neither may be used, the necessary agitation beingproduced by the pump 21, and the kitnetic energy. of the fluid mass asit is discharged from the conduit 21', into the receptacle 1. In theapparatus as shown no means internal or extraneous are shown forproviding a itation to that part of the receptacle 1, ying' below thelowest of the stirring arms 4, or below the inlets 6, for hydraulicagitation, thus providing conditions that permit the solid constituentof the fluid mass, as well as the heavier separated material, (whichconsists of particles lar r in size than the sand used as the so 'dconstituent of the fluid mass) to settle together in the discharge tube8, and in the lower part of the receptacle 1.

The peculiar advantage of this method is found in the ability todischarge the materials without the use of two valves operatedalternately to trap out material as is practiced in the operation ofapparatus similar to the Robinson coal washer, and in the utilization ofthe settled constituent of the different specific gravitie's whichconsists inintroducing said materials. into a fluid mass consisting ofan agitated mixture of comminuted solid matter and liquid, in camaterial of less specific gravity than sai fluid mass to flloag in saidfluiilfi mass, in causin materia o eater spec' c avity than in fluidmass to sink in saifi fluid mass, -in sufliciently reducing theagitation of said fluid mass in the region into which said region tofall with said heavier ma terial, whereby the voids between theparticles of said heavier material become substantially filled with saidcomminuted matter and whereby liquid which in the fluidic portion ofsaid fluid mass separates said particles of comminuted solid matter islargely displaced, in causing said comminuted matter to act as conveyingand restraining element in any further movement of said heavier materialand in removing said heavier material together with said comminutedsolid matter.

2. ,A method for separating materials of different specific gravitieswhich consists in introducing said materials into a fluid massconsisting of an agitated mixture of comminuted solid matter and liquid,in causing material of less specific gravity than said fluid mass tofloat in said fluid mass, in

causing material ofgreater specific gravity than said fluid mass to sinkin said fluid mass, in sufliciently reducing the agitation of said fluidmass in the region into which said heavier material is settling to causethe solid constituents of said fluid mass in said region to fall withsaid heavier material, whereby the voids between the particles of saidheavier material become substantially filled with said comminuted matterand of said fluid mass separates said particles of comminuted solidmatter is largely displaced, in causing said comminuted matter to act asconveying and restraining element in an further movement of said heaviermaterial, in removing said heavier material together with saidcomminuted solid matter and in removing from said fluid mass thematerial floating therein.

I THOMAS M. CHANCE.

Witnesses:

H. M. CHANGE, GARL'K. SCHULZE.

whereby liquid which in the fluidic portion

